重组蜥蜴利什曼原虫载体疫苗的研制现状

蜥蜴利什曼原虫是一种新型疫苗载体,它已用于研发婴儿利什曼原虫、硕大利什曼原虫、刚地弓形虫、人免疫缺陷病毒1型、人乳头瘤病毒16型、丙型肝炎病毒疫苗。本文就重组蜥蜴利什曼原虫载体疫苗研制现状进行综述。     

刚地弓形虫亲环蛋白基因TgCyP真核表达质粒的构建及其在Hela细胞内的表达

亲环蛋白(cyclophilin,CyP)是一类广泛存在于原核和真核生物体内的胞溶性蛋白,是刚地弓形虫(Toxoplasma gondii)速殖子的主要成分,能够诱导产生IL-12和IFN-γ,在控制弓形虫急性感染过程中起重要作用.本研究根据GenBank发表的TgCyP基因序列,设计并合成一对包含BamHⅠ和EcoRⅠ酶切位点的引物,以cDNA为模板,应用PCR技术扩增TgCyP基因.PCR产物连接到pMD18-T克隆载体.用限制性内切酶BamHⅠ和EcoRⅠ双酶切克隆载体,将TgCyP目的基因克隆到载体pVAX1,构建真核表达质粒pVAX1-TgCyP.将真核表达质粒转染Hela细胞,利用间接免疫荧光检测其在Hela细胞内的表达情况.结果表明扩增的TgCyP基因与GenBank上相应基因序列(U04633.1)的一致性达100%,构建的真核表达质粒pVAX1-TgCyP能在转染的Hela细胞中表达,其表达产物与刚地弓形虫阳性血清具有免疫反应性.本研究表明TgCyP有望作为弓形虫疫苗的候选抗原,将为进一步研究该质粒的动物免疫试验奠定基础.     

新培斯病毒介导的病原体疫苗研制现状

新培斯病毒引起的新培斯热是一种自然疫原性疾病。该病毒可诱导感染的宿主产生细胞、体液和黏膜免疫应答,通过分子生物学技术可改造为理想的疫苗载体,从而表达病毒、寄生虫和细菌等病原体的多种蛋白抗原。这些病原体包括汉城病毒、拉克罗斯病毒、委内瑞拉马脑炎病毒、风疹病毒、狂犬病毒、伪狂犬病毒、口蹄疫病毒、丙型肝炎病毒、麻疹病毒、Ⅰ型人类免疫缺陷病毒、日本脑炎病毒、传染性胃肠炎病毒、单纯疱疹病毒1型、刚地弓形虫、约氏疟原虫、埃及伊蚊、结核分枝杆菌和炭疽杆菌等。本文简要综述新培斯病毒介导的病原体疫苗研制现状。     

刚地弓形虫基因工程疫苗

弓形虫疫苗是预防弓形虫感染的最有效手段之一。随着生物学研究技术的不断进步,弓形虫疫苗的研究也不断深入完善。本文介绍了近年来发展起来的基因工程疫苗的最新研究现状及进展,以期望在对现有研究成果总结的基础上,为大家以后的研究提供新的视角和方向。     

重组伪狂犬病毒疫苗研制现状

伪狂犬病毒引起的伪狂犬病是一种常见的动物传染病。伪狂犬病毒可诱导感染的宿主产生细胞、体液和黏膜免疫应答,可通过分子生物学技术改造为理想的疫苗载体,从而表达寄生虫、细菌和病毒的多种蛋白。这些病原体包括刚地弓形虫、日本血吸虫、马尔他布鲁菌、猪园环病毒Ⅱ型、猪细小病毒、日本脑炎病毒、猪瘟病毒、猪繁殖与呼吸综合征病毒、口蹄疫病毒、猪流感病毒、狂犬病毒和犬瘟热病毒等,本文拟就这方面的研制现状进行综述。     

猫与人畜共患病

猫是多种人畜共患病的传播者,现介绍以下几种病供参阅。弓形虫病由弓形虫属、刚地弓形虫引起的一种原虫病。本病是世界性分布,具有广泛的自然疫源性。人感染后多呈隐性感染,免疫力低下的个体可出现严重症状。本病临床表现复杂,主要侵犯眼、脑和淋巴结等部位。猫和某些猫科动物为弓形虫病的主要传染源。传播途径可分为先天性和获得性两种。先天性为胎儿在子宫内从母体获得感染,妇女妊娠期感染本病后,可通过胎盘感染胎儿,胎儿也可摄入羊水而感染。获得性感染     

弓形虫与宿主细胞相互作用研究进展

刚地弓形虫(Toxoplasma gondii)在细胞内严格寄生,因此它能引起哺乳类宿主(包括人类)细胞的感染。凋亡在宿主细胞与弓形虫的相互作用中发挥着重要的作用。在未受感染的宿主细胞中,凋亡被间接机制所限制,因而宿主细胞能够对弓形虫发生炎症反应。与之相反,在被感染的宿主细胞中,由于凋亡信号级联反应直接受到了干扰,从而抑制了宿主细胞凋亡,这就有利于弓形虫在宿主细胞内的生存和发育。值得注意的是,弓形虫调节和抑制凋亡的两种能力,需要一个精密的调节系统来调控弓形虫和宿主细胞的相互作用,以维持弓形虫稳定的持续感染。重点从弓形虫有关的宿主细胞的凋亡方面进行了介绍。     

弓形虫MIC2胞质尾段蛋白及其多克隆抗体的制备

目的:制备弓形虫微线体蛋白2胞质尾段(MIC2C)蛋白片段及其多克隆抗体。方法:以弓形虫cDNA文库为模板,PCR扩增135bp MIC2C基因片段,构建MIC2C/pGEX-4T-1原核表达系统;IPTG诱导表达GST-MIC2C融合蛋白;用纯化的融合蛋白加免疫佐剂背部皮内注射免疫新西兰兔,制备多克隆抗体,亲和层析纯化并分析抗体的效价。结果:构建了MIC2C原核表达系统,表达并纯化了GST-MIC2C融合蛋白,蛋白的浓度为3.07mg/ml;获得了抗该蛋白的兔源性抗血清,纯化后的多克隆抗体效价为1:16 000。结论:在体外制备并纯化了GST-MIC2C融合蛋白及其多克隆抗体,为后续弓形虫入侵机制的研究奠定了基础。     

弓形虫MIC6突变体的构建及其特性分析

目的:体外构建弓形虫微线体蛋白6(MIC6)突变体并分析其特性。方法:利用基因定点突变的方法,将MIC6蛋白羧基端(MIC6C)的348位色氨酸的碱基突变为缬氨酸的碱基,PCR扩增MIC6C W/V突变体基因片段;构建MIC6C W/V/pGEX-4T-1重组原核表达系统,IPTG诱导表达GST-MIC6C W/V突变体蛋白。以该蛋白为探针蛋白与弓形虫裂解液进行GST沉降实验,SDS-PAGE及Western blot分析。结果:获得了MIC6C W/V突变体基因片段,制备了GST-MIC6C W/V突变体蛋白;MIC6C W/V突变体蛋白的沉降产物中未见蛋白条带,而MIC6C蛋白(未突变蛋白)的产物中有一蛋白条带,且能被抗醛缩酶抗体识别。结论:在体外获得了MIC6突变体;MIC6突变体失去了与醛缩酶作用的特性。     

艾滋病与机会性致病原虫感染

艾滋病（ＡＩＤＳ）是当前世界上严重威胁人类健康的最疑难病症,危及ＡＩＤＳ病人生命的机会性致病原虫感染,已引起高度重视。卡氏肺孢子虫可引起子卡氏肺孢子虫肺炎,是ＡＩＤＳ病人最危险机会性感染病原体之一,刚地弓形虫主要成弓形虫脑病,是导致ＡＩＤＳ病人死亡的重要原因之一,隐孢子虫和贾第虫可引起严重腹泻,患者可因体质消耗而死亡,对这４种原虫感染做出早期诊断,及时治疗,是减少ＡＩＤＳ病人死亡率的重要措施之一。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.